The invention relates to apparatus for controlling the extent of movement of hydraulic components and more particularly to apparatus adapted for external attachment to hydraulic cylinders to control the stroke thereof.
It is known to provide fluid-pressure cylinder and piston units, on for example tractor-associated agricultural equipment, with stops co-operative between the cylinder and piston to positionally determine the extent of relative movement therebetween.
One such example is to be found in U.S. Pat. Ser. No. 2,442,306 (McCormick). In this system we have the situation where the fluid-pressure cylinder is exhausted, for example, to allow the piston rod to retract when the agricultural tool is lowered. To ensure lowering to the same extent, a stop is provided which is adjustable to achieve variation in the extent of distance travelled. McCormick discloses a construction in which a stop is adjustable by means of the selective position of one or more pins on a rod carried yoke.
In another example, namely U.S. Pat. No. 2,615,430 (Fletcher), an adjustable stop is utilized to operate a control valve which cuts off the discharge of exhausting fluid to achieve the same general end result, that is, when the fluid exhaust is cut off, the piston will stop at a predetermined point.
In both of the aforementioned prior arrangements, it was necessary to provide complex fluid power units and control systems to achieve the stroke limiting feature.